The invention relates to a driving device for a sliding wing of a sliding window or a sliding door, comprising a screw rotatably mounted in stationary bearings and driven by a motor, a screw nut being axially displaceably arranged on the screw and non-rotationally retained by a stationary guide, and being in drive connection with the sliding wing, e.g. via a catch.
Automatic opening and closing of sliding windows or sliding doors is primarily desirable if the sliding wings to be moved have large dimensions, have a large mass and/or a stiff guide is provided for the sliding movement of the respective sliding wing. On the other hand, an easy-running guide of manually moved sliding wing often has the consequence that the respective sliding wing is pushed too strongly forwards or back during manual opening of closing, so that it hits too hard against abutments, such as a vertical framework section.
In the not previously published older Austrian Patent Application A 307/98, a motor drive for sliding wings has been suggested, wherein a toothed rack on the lower side of the respective sliding wing cooperates with a toothed wheel stationarily attached on the framework which is driven by an electric motor. Although this sliding wing driving device is quite advantageous, there are instances in which it cannot be used because it is necessary to attach the toothed wheel in a central region of the respective sliding window or the respective sliding door in order that the associated sliding wing may be moved past the toothed wheel into the opened position. In doing so, it is, however, necessary that the toothed wheel passes through corresponding window frame parts in this central region, resulting in accommodation and sealing problems, for instance in case of outer wings or outer windows. An attachment of the driving unit proper lateral in relationship to the sliding window or the sliding door would thus be desirable. As such, this would be attainable by a driving device comprising a screw, as it is known, e.g., from DE 2 819 424 A and DE 2 436 171 A in connection with sliding doors of vehicles etc. These known driving devices are, however, provided on the upper side of suspended sliding wings, where the screw nut passed by the screw is fixedly connected with the associated sliding door wing via a fork. These known driving devices are, however, not or poorly suited in instances where only a narrow space is available because these driving devices have complex constructions requiring quite a lot of space.
In view of a space-saving, not very massive construction it would be particularly desirable to be able to use comparatively slight dimensioned driving screws which would be quite sufficient to obtain the desired sliding wing forward movement, if no loads are to be accommodated by the screws. In doing so, however, it has been shown that a mere end-side bearing of the screw results in saggings and oscillations in the middle portion of the screw so that not only an entrainment of the sliding wing is no longer ensured by the screw nut, but also damage to the sliding wing-screw-assembly may occur. It must be taken into consideration that, e.g., the sliding wings of sliding windows often may have widths of 1.5 m or 2 m and more so that the appropriate screws must have lengths of 3 m or 4 m, or more.
It is now an object of the invention to provide a sliding wing driving device of the initially mentioned type which facilitates the use of comparatively slight-dimensioned screws and their accommodation in the respective frame construction of the sliding door, or the sliding wing, respectively, and where a bending or oscillating of the screw during operation nevertheless is safely avoided.
The inventive driving device of the initially mentioned type is characterized in that at least one movable bearing element is arranged between the stationary bearings, which is axially freely movable along the screw and non-rotationally retained, the at least one movable bearing element being jointly movable by the screw nut during displacement of the latter.
With such an embodiment, it is always possible to ensure an additional supporting or bearing of the screw by the movable bearing element in a more or less central region of the screw, or in the vicinity of the screw nut, respectively, so that particularly in the critical region, the rotating screw will be retained against bending or oscillating, respectively. In this manner, also engagement of the catch provided on the screw nut with the sliding wing to be driven can be maintained, this engagement as a rule being obtained by a simple stop which now is kept, without movement, in abutment on the associated part of the sliding wing, instead of hitting against it in accordance with oscillations of the screw. The screw traverses the movable bearing element freely, i.e. without thread engagement, so that the movable bearing element is freely displaceable on the screw, and therefore it is simply jointly moved with the screw nut when the latter is displaced and it abuts against this movable bearing element. During rearward movement of the screw nut, the latter may entrain the movable bearing element, e.g. via a pulling connection, such as a pulling rod or rail, in the manner of dragging it along.
An additionally improved support and securing of the screw in the region of the screw nut is obtained if at least one movable bearing element is provided on each side of the screw nut. In doing so, the total of at least two movable bearing elements are located at a certain distance from each other for a distributed screw support, and when driving the screw and thus displacing the screw nut, the latter always takes along one of the movable bearing elements by pushing it ahead in front of it, and the other movable bearing element is dragged along, so that also in this instance the entrainment, or co-displacement, described is ensured. Here, it is also suitable to directly interconnect the movable bearing elements instead of connecting them to the screw nut, so that always that bearing element which is pushed forwards by the screw nut will drag along the (one or more) other bearing element(s).
To connect the movable bearing elements, pulling rods, as already mentioned, may be used, e.g. with end-side abutments on the outer side of the bearing elements or in fixed connection therewith, the pulling rods engaging in bores provided in the bearing elements and optionally passing through the same. A particularly simple and space-saving, light-weight, yet nevertheless efficient construction is, however, obtained if the the movable bearing elements are interconnected by at least one flexible pulling element, such as a wire, a cord or the like.
For the movable bearing elements, separate guiding rods or guiding rails could be provided so as to hold them against rotation, yet for a simple embodiment doing away with additional components it is advantageous if the movable bearing element(s) is/are block-shaped and is/are slidingly received in a guiding channel of a horizontal section guiding rail of the stationary framework. In this embodiment, thus, the movable bearing elements are directly accommodated in a section guiding rail of the framework of the sliding wing which is already present to guide the sliding wing. In particular, for having to design the driving device merely with a view to the horizontal displacement movement of the sliding wing and to free it from any loads, the section guiding rail can take up the entire weight of the sliding wing, and in this context it is, therefore, particularly suitable if the sectional guiding rail in which the movable bearing elements are accommodated is the lower guiding rail of the stationary framework. Suitably, the guiding channel then also receives the block-shaped screw nut.
In this embodiment, thus the movable bearing elements and the screw nut are consecutively arranged along the screw within the guiding channel, and to avoid a connection of the movable bearing elements via projections or the like outwardly projecting beyond the guiding channel, it has proven particularly advantageous if the at least one pulling element freely traverses a bore or a longitudinal recess in the screw nut. Preferably, two wires, cords (or rods) are provided which extend on either side of the screw and pass through the screw nut so as to safely avoid a possible wedging of the dragged along bearing element in the guiding channel.
In the present screw driving device, the screw may be driven from one side of the sliding window, or sliding door, respectively, wherein, however, the framework in a vertical, lateral frame part generally offers little space for accommodating the driving motor. However, in general, space conditions on the lower side of the sliding window or the sliding door are more favorable, and accordingly it is advantageous if the the framework accommodates the motor in a recess in the lower frame part, which motor drives the screw via a toothed belt or a chain arranged in a lateral frame part.
For a particularly simple coupling of the sliding wing with the screw nut it has proven suitable if the block-shaped screw nut comprises a pin-shaped catch which projects through a slit-shaped longitudinal opening of the sectional guiding rail and engages a section-frame of the sliding wing.
With a view to a lasting, weather-proof embodiment, it is also advantageous if the movable bearing element(s) is/are made of a highly polymerized plastics, such as, e.g., polyoxymethylene or polyamide. For the guidance on the screw it is, moreover, suitable if the movable bearing element(s) comprises/comprise a reinforcing bearing sleeve, preferably made of metal, which is traversed by the screw.
On the other hand, it is advantageous for a stable configuration if the movable bearing element(s) is/are made of metal, preferable of brass.